DEVICE FOR ADJUSTING DISTANCES BETWEEN AXES OF CYLINDERS IN A PRINTING MACHINE

Abstract: In a printing machine (frame etc. not shown) a counterpressure cylinder (1) is rotatably supported in cylindrical bearing housings (5) bordering on the counterpressure cylinder (1) and being held rotatably in the printing machine by means of rollers (10, 11, 12, 13). Opposite to each of these bearing housings (5) is a bearing housing (8) for a plate cylinder (2), the latter bearing housings (8) bordering on the plate cylinder (2) and likewise being held in the printing machine between rollers (14, 15, 16, 17). One of these rollers (14) is rotatably supported in the bearing housing (5) for the counterpressure cylinder (1), while two of the rollers (16, 17) act on the bearing housings (8) for the plate cylinder (2) with an elastically yielding pressing force. By means of an actuating mechanism (21, 22, 23, 24), each of the bearing housings (5) for the counterpressure cylinder (1) can be turned from a position, in which the axis of the roller (14) in the bearing housing (5) is co-planar with the axes of the counterpressure cylinder (1) and the plate cylinder (2), to a non-co-planar position, thus reducing the distance between the axes of the cylinders (1, 2).

Description: DEVICE FOR ADJUSTING DISTANCES BETWEEN AXES OF CYLINDERS IN A PRINTING MACHINE. TECHNICAL FIELD The present invention relates to a device for adjusting the distance betweeen the axis of a counterpressure cylinder and a plate cylinder, possibly also between the axis of the plate cylinder and an inking cylinder, in a printing machine. DISCLOSURE OF THE INVENTION It is the object of the present invention to provide a device of the kind referred to above, with which it is possible I . during the operation of the printing machine to adjust the distance between the axes of a counterpressure cylinder and a plate cylinder, and possibly so that this distance is shorter at one end of the cylinders than at the other end in order to achieve a uniform deposition of ink across the width of the printed web, when the printing area of the plate cylinder is larger at one end than at the other, and II. when the printing machine is inoperative, to set such a distance between the axis of the counterpres- sure cylinder and the plate cylinder, possibly also between the axis of the latter and the inking cylin¬ der, that the cylinders do not press against or abut against each other, as such a pressure against the plate cylinder entails a risk of deformation of the printing plate on the plate cylinder, thus causing later prints to be slurred or subject to other dete¬ rioration. The stated object is achieved by means of the features set forth in the claims. With such a device, it is possible during the operation of the printing machine to adjust individually the distance between the axes of a counterpressure cylinder and a plate cylinder at each end of the cylinders, and also in the in¬ operative condition of the printing machine to set the dis¬ tances between the axes of the counterpressure cylinder and the plate cylinder, possibly also between the axes of the latter and the inking cylinder, in such a manner, that these cylinders do not press against each other. BRIEF DESCRIPTION OF THE DRAWING In the following detailed portion of the present description, the invention will be explained in more detail with reference to the relevant parts of a printing machine shown in the drawing, in which Fig. 1 diagrammatically and in perspective shows a part of a printing machine comprising a counterpressure cylinder, a plate cylinder and an inking cylinder as well as devices according to the present invention, and Fig. 2 shows the part of the printing machine shown in Fig. 1, as viewed from the side. DESCRIPTION OF THE PREFERRED EMBODIMENT For ease of understanding, the drawing shows solely those constructional elements in the printing machine being of immediate importance with a view to explaining the present invention, while constructional details, such as the frame of the printing machine and the means for securing and sup¬ porting of the elements shown in this frame, have not been included, such details being obvious or near-at-hand to a person skilled in this particular art. Figure 1 shows a counterpressure cylinder 1, a plate cylin¬ der 2 and an inking cylinder 3. The stub shafts 4 of the counterpressure cylinder 1, of which only one is shown, are rotatably supported in bearing hou¬ sings 5 bordering on the counterpressure cylinder 1 and being substantially cylindrical and having the same diameter as the counterpressure cylinder 1. Each of the bearing housings 5 is rotatably secured in the frame of the machine (not shown) by means of four rollers 10, 11, 12 and 13. As indicated with arrows A, the rollers 10 and 11 may be adjustable rela¬ tive to the frame of the printing machine. In a similar manner, the bearing stub shafts 7 of the plate cylinder 2, of which likewise only one is shown in the draw¬ ing, are rotatably supported in bearing housings 8 bordering on the plate cylinder 2. Each of the bearing housings 8, being shown on the drawing as being cylindrical with the same diameter as the plate cylinder 2, although it does not neces- sarily have to be so, is secured in a non-rotatable manner, e.g. guided by a key in a keyway (not shown) in the bearing housing 8, and held securely in the frame of the printing machine by means of four rollers 14, 15, 16 and 17 (Fig. 2). Of these, the roller 14 is rotatably supported in the adjacent bearing housing 5 for the counterpressure cylinder 1 with its rotational axis parallel to the axis of the coun¬ terpressure cylinder 1 and in such a manner, that part of the cylindrical surface of the roller 14 protrudes somewhat beyond the cylindrical surface of the bearing housing 5. The rollers 16 and 17 are in abutment against the mainly cylin¬ drical surface of the bearing housing 8 with an elastically yielding force, and the roller 15 is, in a manner to be explained below, associated with the stub-shaft bearing arrangement for the inking cylinder 3. Each of the bearing housings 5 for the counterpressure cy- linder 1 is provided with a toothed sector 21 in engagement with another toothed sector 22 on a lever 23, the pivoting axis of which is fixed relative to the frame of the printing machine, and the lever 23 is linked to an actuating mechanism in the form of a piston-cylinder unit 24 being fixedly se¬ cured to the frame (not shown) of the printing machine. The manner of functioning of the device for adjusting the distance between the axis of the counterpressure cylinder 1 and the plate cylinder 2 will now be described with reference to the adjusting mechanism shown to the right in Fig. 1 and in Fig. 2, the two mechanisms being identical in construction and function. When fluid under pressure is controlled to flow towards or away from the piston-cylinder unit 24, the piston rod in this unit moves inwardly, thus moving the lever 23 towards the right in Figs. 1 and 2. This causes the toothed sector 22 to turn clockwise and hence the toothed sector 21 and with it the bearing housing 5 anticlockwise. This again causes the roller 14 to swing away from its position shown in Fig. 2, in which its axis is co-planar with the axes of the coun¬ terpressure cylinder 1 and the plate cylinder 2, to a lower position. Since the roller 14 abuts against the bearing housing 8 of the plate cylinder 2, its change in position causes the bearing housing 8, influenced by the elastically yielding force from the rollers 16 and 17, to move towards the bearing housing 5 for the counterpressure cylinder 1, i.e. the axes of the plate cylinder 2 is made to approach the axes of the counterpressure cylinder 1. This turning of the bearing housing 5 and the ensuing swin¬ ging movement of the roller 14 may be continued, although it is necessary for the roller 14 to be continously in abut- ment against the bearing housing 8 in order to support this effect. Normally, the flow of pressure fluid to and from the two piston-cylinder units 24 will be controlled in unison, so that the axes of the counterpressure cylinder 1 and the plate cylinder 2 remain parallel. In case the printing area of the plate cylinder 2, i.e. the pattern or image to be printed, is larger at one end than at the other, measures may be taken for individually controlling the flow of pres¬ sure fluid to and from each of the two piston-cylinder units 24 in such a manner, that the axes of the counterpressure cylinder 1 and the plate cylinder 2 are not parallel. When the printing machine is inoperative, the arrangement is such, that the piston-cylinder unit 24 automatically moves the bearing housing 5 to the position shown in Fig. 2, in which the axis for the rollers 14 is co-planar with the axes of the counterpressure cylinder 1 and the plate cylinder 2, thus setting the distance between these axes to a maximum. This distance should, of course, not be greater than to ensure that the driving pinions 25 and 26 for the counter¬ pressure cylinder 1 and the plate cylinder 2 respectively always remain safely in mesh. It does, of course, lie within the scope of the invention to replace the operating mechanism 21, 22, 23 and 24 for turning each of the bearing housings 5 with an equivalent operating mechanism, e.g. a screw-spindle drive. Each of the stub shafts 18 of the inking cylinder 3, of which only one is shown in the drawing, is rotatably sup¬ ported between two pairs of mutually facing rollers 19 and 20, the rotational axes of which are parallel to the axis of the inking cylinder 3. The shafts for the rollers 19 are rigidly connected, e.g. by means of a plate member (not shown), with the shaft for the roller 15 in such a manner, that the cylindrical surface of the latter protrudes somewhat beyond the cylindrical surface of the inking cylinder 3. Further, these shafts and hence the rollers 19 and the roller 15 are supported for limited swinging movement about the axis of the inking cylinder 3 by means of an operating me¬ chanism (not shown), e.g. a mechanism of the same kind as or similar to the operating mechanism 21, 22, 23 and 24 described above with reference to the device for adjusting the distance between the axes of the counterpressure cylinder 1 and the printing cylinder 2. By swinging the roller 15 about the axis of the inking cy¬ linder 3, the roller 15 can be moved from a position, in which its axis is co-planar with the axes of the plate cy- under 2 and the inking cylinder 3, to a position outside of the plane through these axes, and in this manner it is possible to adjust the distance between the axes of the plate cylinder 2 and the inking cylinder 3 in a similar way as explained above with reference to the axes of the coun- terpressure cylinder 1 and the plate cylinder 2. Primarily, however, the operating mechanism (not shown) for swinging the rollers 19 and the roller 15 is adapted, when the printing machine is inoperative, to automatically adjust the roller 15 for each end of the inking cylinder 3, to a position co-planar with the axes of the plate cylinder and the inking cylinder and hence adjust the distance between these two axes to a maximum, not greater than always to secure a safe mesh between the driving pinions 26 and 27 for the plate cylinder 2 and the inking cylinder 3 respec¬ tively. Also with this device for adjusting the distance between the axes of the plate cylinder 2 and the inking cylinder 3, the two operating mechanisms for the two ends of the inking cylinder 3 may, of course, be adapted to function both in unison and individually, so that in the latter case, the axes may also be adjusted to a non-parallel relation. Even though the devices according the present invention have been described above with reference to a printing ma¬ chine for flexography, it will easily be appreciated that similar, modified devices based on the principles of the present invention may be used in connection with other forms of printing, such as letterpress printing, offset printing, photogravure or rotogravure and silk-screen printing. LIST OF PARTS A Arrow 1 Counterpressure cylinder 2 Plate cylinder 3 Inking cylinder 4 Stub shaft 5 Bearing housing 7 (Bearing) stub shaft 8 Bearing housing 10 Roller 11 Roller 12 Roller 13 Roller 14 Roller 15 Roller 16 Roller 17 Roller 18 Stub shaft 19 Roller 20 Roller 21 Toothed sector 22 Toothed sector 23 Lever 24 Piston-cylinder unit 25 Driving pinion 26 Driving pinion 27 Driving pinion

Claims: CLAIMS . 1. Device for adjusting the distance between the axes of a counterpressure cylinder ( 1 ) and a plate cylinder (2), possibly also between the axes of the plate cylinder (2) and an inking cylinder (3) in a printing machine, charac¬ terized in a) that on both sides, the stub shafts (4) of the coun¬ terpressure cylinder (1 ) are rotatably supported in bearing housings (5) of generally cylindrical shape and bordering on the counterpressure cylinder ( 1 ) , b) that each bearing housing (5) is rotatably held bet¬ ween rollers (10, 11, 12, 13) in the printing machine and comprises a projection, preferably in the form of a roller (14), that is rotatably supported in the bearing housing (5) about an axis parallel to the axis of the counterpressure cylinder (1), and the cylindrical surface of which protrudes somewhat beyond the cylindrical surface of the bearing housing ( 5 ) , c) that the stub shafts (7) of the plate cylinder (2) are likewise rotatably supported in bearing housings (8) of generally cylindrical shape and bordering on the plate cylinder (2), each of said bearing housings (8) being yieldingly held between the roller (14) in the adjacent bearing housing (5) for the counter¬ pressure cylinder (1) and rollers (15, 16, 17) in the printing machine, and d) that a mechanism (21, 22, 23, 24) is provided for turning each bearing housing for the counterpressure cylinder (1) from a position, in which the axis of the roller (14) is co-planar with the axes of the counterpressure cylinder and the plate cylinder (2), and in which the distance between the two last-men¬ tioned axes is at a maximum, to a position, in which the axis of the roller (14) is not co-planar with said two last-mentioned axes, and, e) possibly, that each of the stub shafts (18) of the inking cylinder (3) is yieldingly held between four rollers (19, 20 resp. ) arranged in mutually opposing pairs, in which the shafts for one (19) of the pairs are rigidly connected to the shaft for the roller (15) holding the bearing housing (8) for the plate cylinder (2) and being situated closest to the inking cylinder (3), said rigidly interconnected shafts being capable of swinging to a limited extent about the axis of the inking cylinder (3) in such a manner, that said holding roller (15), the cylindrical surface of which protrudes somewhat beyond the cylindrical surface of the inking cylinder, may be made to swing from a position, in which its axis is co-planar with the axes of the plate cylinder (2) and the inking cylinder (3) and the distance between the two last-mentioned axes is at a maximum, to a position, in which said first-mentioned axis is not co-planar with said two last-mentioned axes. 2. Device according to claim 1, characterized in a) that the bearing housings (5) for the counterpressure cylinder (1) have substantially the same diameter as the latter, and b) that the bearing housings (8) for the plate cylinder (2) have substantially the same diameter as the lat¬ ter. 3. Device according to claim 1 or claim 2, charac- terized in that the mechanism for turning each of the bearing housings (5) of the counterpressure cylinder (1 ) comprises a toothed sector (21) on the bearing housing (5) engaging a toothed sector (22) on a lever (23) pivotably supported in the printing machine, said lever (23) being linked to the piston rod in a piston-cylinder unit (24) actuated by fluid under pressure. 4. Device according to claim 3, characterized in that the two piston-cylinder units (24) are adapted to be controlled both in unison and individually. 5. Device according to any one or any of the preceding claims, characterized by such an arrangement, that when the printing machine is inoperative, each of the rollers (14) will automatically take up the position, in which its axis is co-planar with the axes of the counterpressure cylinder (1) and the plate cylinder (2), and in which the distance between the two last-mentioned axes is at a maximum. 6. Device according to claim 5, characterized by such an arrangement, that in said position of each of the rollers (14), the driving pinions (25, 26) for the counter¬ pressure cylinder (1) and the plate cylinder (2) respectively are in secure interengagement. 7. Device according to claim 1, characterized by such an arrangement, that when the printing machine is in¬ operative, each of the rollers (15) holding the bearing housings (8) for the plate cylinder (2) will automatically swing about the axis of the inking cylinder (3) to that position, in which its axis is co-planar with the axes of the plate cylinder (2) and the inking cylinder (3), and in which it sets the distance between the two last-mentioned axes to be at a maximum. 8. Device according to claim 7, characterized by such an arrangement, that in said position of the rollers (15), the driving pinions (26, 27) for the plate cylinder (2) and the inking cylinder (3) respectively are in secure interengagement.

Inventors: RIIS EINAR KAJ, RIIS, EINAR, KAJ
Applicants: LEOPRINT MASCHINEN GMBH, RIIS EINAR KAJ, RIIS, EINAR, KAJ
Application year: 1994
Main classification: B41F13
IPC codes: B41F13